The DUP leader has denied there is any deal between his party and the UK government to bring back so-called double-jobbing for politicians in Northern Ireland.
"Let me be absolutely clear. There is no agreement between the [UK]government and the DUP on this," Jeffrey Donaldson told reporters at Stormont on Monday.
An amendment to a bill currently being considered by the House of Lords proposes a temporary change in the law on dual mandates which would allow the DUP leader to stand for election to the Assembly while retaining his seat as an MP.
Legislation preventing politicians from holding multiple positions simultaneously came into effect in 2016, forcing a number of MPs to give up their seats in the Assembly.
Supporters argue this would bring the situation in Northern Ireland into line with the rest of the UK, and would promote stability by facilitating a move from the Commons to the Northern Assembly without triggering by-elections.
Mr Donaldson, who is currently the MP for Lagan Valley, has previously said he intends to put his name forward as a candidate in the elections to the Northern Ireland Assembly, which are due to take place by May at the latest.
On Monday Mr Donaldson said the selection process in the Lagan Valley constituency was “ongoing” and, if selected, the decision would be up to voters. “Ultimately, they will decide whether they want their MP to also be an MLA [Member of the Legislative Assembly] and that is called democracy.”
He declined to confirm whether any other DUP MPs intended stand in the Assembly election, and would not confirm reports that a second MP would also seek election to Stormont.
“The bulk of DUP MPs have not put their name forward for selection,” he told the BBC.
The other four parties in the Northern Executive have strongly criticised the move, claiming it is aimed at benefiting the DUP, and have said their MPs will not stand in the Assembly elections.
The Deputy First Minister, Michelle O’Neill, accused the UK government of “interfering to serve only the DUP” and to “prop up the DUP in the election campaign.
“This is the very same DUP that are threatening the stability of politics ... and the British government have rewarded them over the weekend by propping them up in terms of giving Jeffrey Donaldson an each-way bet,” she said.
The SDLP MP Claire Hanna told the BBC it "feels very much like a stroke and it's a stroke to benefit Jeffrey Donaldson."
The Ulster Unionist leader Doug Beattie described it as a "scam" and "a subversion of our democracy" which was "wrong."
In a statement on Monday the shadow Northern Secretary, the Labour MP Peter Kyle, called on the UK government to withdraw its amendment as it does not have cross-party consensus and said if it proceeded Labour would oppose it.
“To force this through now risks further destabilising an already fragile political landscape in the approach to the elections,” he said.
A spokesman for the Northern Ireland Office confirmed the Government had tabled an amendment to the Northern Ireland (Ministers, Elections and Petitions of Concern) Bill and said it would be subject to the usual parliamentary scrutiny.
Additional reporting - PA.
